Internal combustion engine



VY 26, 1935 c. w. VAN RANST I INTERNAL COMBUSTION ENGINE Patented May 26, 1936 UNITE STATS virer Fries to Packard Motor Car Company,

Detroit,

Mich., a corporation of Michigan Application April 24, 1933, Serial No. 667,547

11 Claims.

This invention relates to internal combustion engines and more particularly to valve gear mechanism.

An object of the invention is to provide a new 5 and novel means for automatically taking up slack or clearance in valve gear mechanism.

Another object of the invention is to provide a valve gear mechanism in which parts are maintained in contact by a hydraulically controlled eccentric member.

A further object of the invention is to provide a novel form of mechanism which is carried by a rock lever of valve gear mechanism for automatically taking up slack.

Still another object of my invention is to provide a hydraulic control for taking up slack in Valve gear mechanism in which the fluid utilized is maintained under substantially uniform pressure.

Other objects of the invention will appear from the following description taken in connection with the drawing, which forms a part of this specication, and in which:

Fig. 1 is a vertical sectional View through an internal combustion engine showing my invention in associated relation;

Fig. 2 is plan view, partly in section, of a part of the valve gear mechanism;

Fig. 3 is a vertical sectional view of a part of the Valve mechanism taken on line 3 3 of Fig. 2;

Fig. 4 is a sectional view of the rock lever taken on line 4 4 of Fig. 3.

Referring now to the drawing by characters of reference, I0 illustrates an in-line internal combustion engine of conventional design. Mounted on the crank case II is a cylinder structure I2 and secured beneath the crank case is the usual bottom cover I3. On top of the cylinder structure is arranged the head I4 which, with the cylinders, forms combustion chambers as indicated at I5. In the cylinders are pistons I6 which are connected to the crank shaft I'I by rods I8. The cam shaft I9 is mounted in the crank case and is driven from the crank shaft in the usual manner.

Carried by the bottom cover is a circulating pump 28 from which lubricant collecting in the crank case is moved to the points of distribution leading to the various engine bearings. A conduit 2| leads from the pump to a drilled passage 22 in the rear wall of the crank case which communicates with a pressure equalizing cylinder 23 through a passage 9. In the equalizing cylinder is a, plunger valve 24 having radial passages 25 (Cl. 12S-90) communicating with an axial passage 28 which extends through one end portion of the plunger. An adjustable cap 2l is arranged in one end of the cylinder and provides a seat for a spring 28 p which bears against the plunger valve and urges it toward the closed end 29 of the cylinder. The cap is secured in position to suitably compress the spring 28 by a locking member 30.

The cylinder is attached to the exterior of the crank case, however, it could be attached within the crank case equally as well, and the cap is formed with an opening 3l to allow escape of lubricant from the associated cylinder from which it ilows back into the crank case through a suitable pipe connection (not shown). A conduit 32 is arranged in communication with a hollow bearing shaft 33 which extends through the rear wall ofthe crank case. Lubricant collecting in the crank case is moved under pressure by the pump 20 through the conduit 2l to the passage 22 from Which it feeds into the cylinder 23 and through the radial passages 25 into the passage 26 when the radial passages register with the passage 9,. From the axial passage 28 the lubricant flows into the conduit 32 and into the shaft 33. When 25 the pressure on the delivery side of the piston valve 24 exceeds the pressure of the spring 28, the valve will be moved toward the opening 3l and will reduce or cut 01T the fluid flowing into the cylinder until the pressure on the delivery Side of the cylinder becomes less than the pressure exerted by the spring 28 whereupon the valve will be moved so that flow therethrough will again be established. In this manner, the fluid pressure in the shaft 33 is automatically maintained sub- 5 stantially constant.

A pair of ports, one of which is indicated at 34, lead to each cylinder and provide for the intake of an explosive mixture and for the exhaust of the burnt charge. Each port has a Valve 0 mechanism associated therewith and, as they are similar, the description of one will suice. Valve 35 controls communication between the combustion chamber I5 and the port 34. This valve reciprocates in a guide 36 through which the stem 45 3'I extends. The usual coil spring 38 is associated with the cylinder block and a retainer 39 to normally seat the valve. A tappet 40 extends through a guide 4I and is operatively associated with the valve guide. The tappet and stem pro- 0 vide a rod structure by means of which the valve is operated.

Intermediate the rod structure and the cam shaft I9 is arranged a rock lever 42 which is pivotally mounted Von the shaft 33. On the free 55 end of the rock lever is arranged a hardened bearing insert 43 which engages with the tappet and also associated with the rock lever is another bearing means which engages the cam I9. This last bearing means includes an eccentric member 44, which is rotatably mounted upon a shaft 45 fixed to the lever, a roller 46 contacting with the cam and suitable roller bearing means, as indicated at 4l, intermediate the roller and eccentric member.

Hydraulic control means is associated with the eccentric member for maintaining the bearing 43 in constant contact with the tappet A0. The rock lever is formed with a cylinder 48 in which reciprocates a plunger 48 having a stem 59 projecting from the cylinder and` arranged to engage with an arm 5I which extends from the eccentric member. The shaft 33 is 'formed with radial ports 52 which communicate with a groove 53 in the pivoted end of the rock lever and a port 54 leads from the groove .to one `end of -the cylinder 48. A one-way valve 55 is arranged in the port 54 and is limited in its movement bya combined closure and stop member 56.

It has been heretofore explained that lubricant flows to the interior of the shaft 3-3 at substantially a constant pressure. vSome of such lubricant will pass through the ports :52, the groove 53, and through the port 54 into the interior of the cylinder exerting pressure against the plunger 49 in a direction tending to rotate the eccentric member clockwise, as viewed .in Fig. 3. It will thus be seen that the veccentric member is, during operation of the engine, .constantly urged in a direction whereby the thicker portion is moved toward the cam to elevate the rock lever toward the --tappet and thus take `up slack between the .bearing member 43 and the tappet. When the lobe of the cam starts to engage the roller 46, the tendency is to rotate the eccentric member on its `bearing in a counterclockwise direction but this will not happen because the ball check valve 5.5 shuts .off any return of the `fluid through the port54 and prevents any clockwise rotation of the arm 5l through means of the plunger and the -established fluid column. As a consequence, the bearing means is held in a substantially positive relation .during actuation of the rock lever so that there will be no slack between bearing member 43 and the tappet or between the roller and the cam. The hydraulically actuated plunger will move the eccentric member in a direction such that the roller tends to rotate toward the cam `and the bearing 43 moves toward the tappet when the roller is -riding up on the cam lobe. It will thus be seen that, during the operation of the Valve.. gear mechanism, slack is automatically taken up so vthat .contraction or expansion thereof and wear `will not vary the timing appreciably and will not be the cause of noise. In order `to hold the plunger in constant contact with the arm 5l, and particularly during low lubricant pressure periods 'such as present in starting, I provide va -coil spring 60 around the stem 5D. ,One -end of the .spring seats in a groove 6l formed near the end of the stem and the other end .of the springseats against a collar 62 bearing against the end .of the cylinder formed on the rock lever. It Will be seen that the spring will hold the plunger stem against the arm A5 I.

Although the invention has been described in connection with a specific embodiment, the principles involved are susceptible of numerous other applications which will readily occur to persons skilled in the art. The invention is therefore to be limited only as indicated by the scope of the appended claims.

What I claim is:

1. Valve gear mechanism comprising a valve operating rod, a cam, a rock lever extending intermediate the cam and the rod, bearing means eccentrically mounted on the lever, said bearing means engaging with the cam, and hydraulically actuated means mounted on the lever and regulating the eccentric position of the bearing means to take up slack in the mechanism.

2. Valve gear :mechanism comprising a valve operating rod, a cam, a rock lever extending intermediate the cam and the rod having a chamber, a plunger slidable in the chamber, rotatable bearing means eccentrically mounted on the lever and engaging the cam, said plunger engaging with the eccentric bearing means to regulate the eccentric position thereof, and hydraulic means urging .the plunger in a .direction to hold the lever in constant-contact with the rod.

3. Valve gear mechanism comprising a valve operating rod, Aa cam, a rock lever extending iin- .termediate the cam and the rod having a chamber, a plunger Aslidable inthe chamber, rotatable bearing means eccentrically mountedon the lever and engaging the cam, said Vplunger engaging with the eccentric bearing means to regulate the eccentric position thereof, and means .-urging the plunger in a .direction to Vhold the lever in constant -contact with the rod.

4. Valve gear mechanism comprising Aa valve operating rod, a cam, a rock lever extending intermediate the cam andthe rod having a chamber, a plunger slidable in the chamber, rotatable bearing means `eccentrically mounted onthelever and engaging the cam, said plunger engaging with the eccentric bearing means to regulate the eccentric position thereof, and automatic means urging the plunger in .a .direction to hold the leverin c onstant contact with the rod.

5. Valve gear mechanism comprising a valve operating rod, a cam, a rock lever extending between the cam and .the rod, bearing means eccentrically mounted on the lever and engaging the cam, an arm .connected -with the bearing means, and means carried by the lever and associated with the arm to automatically regulatethe eccentric .position of the bearing means Vto `take up' slack in the mechanism.

6. `In valve gear mechanism, a valve operating rod, a cam, a rock lever engaging the rod, an adjustable .bearing means carried by the rock lever, said bearing means being engaged by the cam, mechanism .engaging the bearing means to adjust the position thereof, and a hydraulic system exerting pressure against the mechanism to take up slack between the lever and the rod, said system including pressure equalizing means.

'7. In an internal combustion engine, the combination with the valve gear mechanism .including a valve operating rod and a valve operating cam, and the pressure oil circulating system for the engine bearings, of a valve gear take-up mechanism comprising a rock lever extending between the cam and the rod and mounted in a bearing on the engine, said rock lever having an adjustable take-up device and a cylinder, a plunger in the cylinder operating said take-up device, a lead from the engine lubrication system to the bearing of said rock lever and to said cylinder, and a pressure regulating valve in said lead.

8. Valve gear mechanism comprising a valve operating rod, a cam, a rock lever extending in' termediate the cam and rod, an eccentrically mounted bearing on said lever, a roller on the bearing in contact with the cam, an arm on the bearing member, and a hydraulically operated plunger mounted on the lever and engaging said arm to adjust said bearing member and roller.

9. Valve gear mechanism comprising a valve operating rod, a cam, a rock lever extending intermediate the cam and rod, a roller in contact with the cam, an adjustable member supporting the roller and mounted on the lever for taking up slack, and hydraulic means for adjusting said member including an elongated cylinder on the lever itself and extending diagonally thereof with its open end higher than its abutment end, means for feeding oil under pressure to the abutment end of said cylinder, and a plunger mounted in the cylinder and extending into Contact With said member to adjust the latter.

10. Valve gear mechanism comprising a valve operating rod, a cam, a rock lever extending intermediate the cam and rod, a roller in contact with the cam, an adjustable member supporting the roller and mounted on the lever for taking up slack, and hydraulic means for adjusting said member including an elongated cylinder on the lever itself and so mounted that its open end is always higher than its abutment end, meansfor feeding oil under pressure to the abutment end of said cylinder, and a plunger spring pressed against said member and mounted in said cylinder under the pressure of the oil fed thereto.

11. In an internal combustion engine, the combination with a valve operating rod and a valve operating cam, of a pivoted rock lever extending intermediate the cam and the rod, the outer end of said lever being adapted to contact with the rod, rotatable bearing means eccentrically mounted on the lever adjacent its outer end, a roller rotatably mounted on said bearing means and adapted to contact with said cam, said rock lever being formed with a chamber adjacent its pivoted end, a plunger in the chamber having means in contact with said bearing means, and hydraulic means in the chamber urging the plunger in an outwardly direction, for the purpose set forth.

CORNELIUS W. VAN RANST. 

